The Microbiome Explained: What Happens When You Eat Kimchi Or Sauerkraut?
You’ve probably heard that fermented foods are good for your gut, but what actually happens inside your body when you eat something like kimchi or sauerkraut?
These traditional fermented vegetables are more than just tangy, crunchy condiments. They’re microbial powerhouses that directly interact with your gut microbiome - the dynamic ecosystem that influences everything from digestion to immunity to mental health.
In this comprehensive guide, we’ll break down exactly how foods like kimchi and sauerkraut affect your microbiome, what changes take place in your gut, and why this matters for your long-term health.
What Is The Microbiome?
Your gut microbiome is a diverse community of trillions of microorganisms — bacteria, viruses, fungi, and protozoa — living in your digestive tract, primarily the colon. It’s essentially an internal rainforest that plays a vital role in:
Breaking down food
Absorbing nutrients
Regulating immune function
Protecting against pathogens
Producing neurotransmitters and vitamins
According to the NIH Human Microbiome Project, over 1,000 species of bacteria inhabit the human gut.
When in balance, this ecosystem helps maintain health. When it's out of balance (a state called dysbiosis), it can contribute to problems like:
IBS
Obesity
Anxiety & depression
Autoimmune conditions
The Power Of Fermentation
Fermentation is a natural process in which microorganisms — primarily lactic acid bacteria (LAB) — convert sugars and starches in food into acids, gases, or alcohol.
In the case of kimchi and sauerkraut:
Kimchi is a Korean dish made with cabbage, radish, garlic, ginger, and chili, fermented with Leuconostoc and Lactobacillus species.
Sauerkraut is finely cut cabbage fermented by LABs like Lactobacillus plantarum and Leuconostoc mesenteroides.
Fermentation:
Increases probiotic content
Improves nutrient bioavailability
Reduces harmful compounds (like phytates)
Adds unique flavors and textures
The Microbial Profile Of Kimchi And Sauerkraut
Here’s a breakdown of the main probiotic strains found in these foods:
| Microbe | Found In | Health Function |
|---|---|---|
| Lactobacillus plantarum | Both | Anti-inflammatory, gut lining support |
| Leuconostoc mesenteroides | Both | Initiates fermentation, pathogen defense |
| Lactobacillus brevis | Kimchi | Antioxidant production |
| Weissella cibaria | Kimchi | Oral and gut microbiota benefits |
| Lactobacillus sakei | Kimchi | Supports immune function |
Fun fact: Kimchi contains over 900 different strains of bacteria, many of which are beneficial and not found in yogurt or supplements.
What Happens In Your Gut When You Eat Kimchi Or Sauerkraut?
When you consume a forkful of raw, unpasteurised kimchi or sauerkraut:
Probiotics enter your digestive system and move through the stomach.
Some are destroyed by stomach acid, but many survive (especially in fermented fibre).
The survivors reach your colon and begin interacting with your existing microbiota.
These bacteria:
Colonise temporarily and improve diversity
Outcompete harmful bacteria (like Clostridium difficile)
Enhance production of short-chain fatty acids (SCFAs) like butyrate
Stimulate your immune cells
Trigger the release of neurotransmitters like serotonin and GABA
These changes can occur within just 24 - 48 hours, although long-term impact depends on consistent intake.
Health Benefits Backed By Science
Improved Digestion
LABs aid in breaking down lactose, fiber, and antinutrients — improving digestion and nutrient absorption.
Immune System Modulation
Fermented foods strengthen gut barrier integrity and help regulate inflammatory responses.
Reduced Inflammation
Kimchi has been shown to lower markers of systemic inflammation — like TNF-α and CRP.
Weight & Metabolic Regulation
Certain probiotics in kimchi and sauerkraut promote fat oxidation and insulin sensitivity.
Mental Health & Mood
A 2022 paper in Frontiers in Psychiatry linked fermented food intake to reduced anxiety and depression symptoms.
………………….Want more? See our guide: The Gut-Brain Connection: How Fermented Foods Impact Mental Health
Kimchi vs. Sauerkraut: Which Is Better?
| Feature | Kimchi | Sauerkraut |
|---|---|---|
| Origin | Korea | Central & Eastern Europe |
| Spice Level | Medium to Hot | Mild |
| Microbial Diversity | Higher due to variety of veggies | Less, but still beneficial |
| Fermentation Time | Shorter (3–5 days) | Longer (2–3 weeks) |
| Nutrients | Vitamin C, A, capsaicin | Vitamin K2, C |
Verdict: Both are excellent for your microbiome. Kimchi has a spicier flavour and broader microbial profile, while sauerkraut offers a milder option rich in Vitamin K2. Add both to your daily food intake with our Ferment Full Works.
Add Kimchi And Sauerkraut Into Your Daily Diet
How To Add Them To Your Diet
Tips for daily intake:
Add 1 - 2 tablespoons per meal as a condiment
Mix into salads, wraps, or rice bowls
Use kimchi in omelets, stews, or fried rice
Add sauerkraut to sandwiches or grilled veggies
Pro tip: Always choose raw, unpasteurised versions from the fridge section, not the shelf-stable, heat-treated kind.
Quality Matters: Choosing The Right Fermented Products
Look for:
“Live & active cultures” on the label
Ingredients like salt, water, and vegetables only
No added vinegar or preservatives
Glass jars (less chance of chemical leaching)
What It All Means
Your microbiome is a living, evolving system and fermented foods like kimchi and sauerkraut are among the most powerful tools for keeping it healthy. They don’t just “add probiotics” they shift your microbial balance, strengthen your immune system, and promote better digestion, clearer thinking, and emotional resilience.
So next time you reach for something fermented, remember: you're not just feeding yourself, you're feeding trillions of microscopic allies inside you.
References And Further Reading
Harvard T.H. Chan School of Public Health – The Microbiome